src/components/search_provider_logos/logo_cache.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "components/search_provider_logos/logo_cache.h"
   6
   7 #include "base/file_util.h"
   8 #include "base/json/json_reader.h"
   9 #include "base/json/json_writer.h"
  10 #include "base/strings/string_number_conversions.h"
  11 #include "base/values.h"
  12
  13 namespace {
  14
  15 // The cached logo metadata is persisted as JSON using these keys.
  16 const char kSourceUrlKey[] = "url";
  17 const char kExpirationTimeKey[] = "expiration_time";
  18 const char kCanShowAfterExpirationKey[] = "can_show_after_expiration";
  19 const char kFingerprintKey[] = "fingerprint";
  20 const char kOnClickURLKey[] = "on_click_url";
  21 const char kAltTextKey[] = "alt_text";
  22 const char kMimeTypeKey[] = "mime_type";
  23 const char kNumBytesKey[] = "num_bytes";
  24
  25 bool GetTimeValue(const base::DictionaryValue& dict,
  26                   const std::string& key,
  27                   base::Time* time) {
  28   std::string str;
  29   int64 internal_time_value;
  30   if (dict.GetString(key, &str) &&
  31       base::StringToInt64(str, &internal_time_value)) {
  32     *time = base::Time::FromInternalValue(internal_time_value);
  33     return true;
  34   }
  35   return false;
  36 }
  37
  38 void SetTimeValue(base::DictionaryValue& dict,
  39                   const std::string& key,
  40                   const base::Time& time) {
  41   int64 internal_time_value = time.ToInternalValue();
  42   dict.SetString(key, base::Int64ToString(internal_time_value));
  43 }
  44
  45 }  // namespace
  46
  47 namespace search_provider_logos {
  48
  49 LogoCache::LogoCache(const base::FilePath& cache_directory)
  50     : cache_directory_(cache_directory),
  51       metadata_is_valid_(false) {
  52   // The LogoCache can be constructed on any thread, as long as it's used
  53   // on a single thread after construction.
  54   thread_checker_.DetachFromThread();
  55 }
  56
  57 LogoCache::~LogoCache() {
  58   DCHECK(thread_checker_.CalledOnValidThread());
  59 }
  60
  61 void LogoCache::UpdateCachedLogoMetadata(const LogoMetadata& metadata) {
  62   DCHECK(thread_checker_.CalledOnValidThread());
  63   DCHECK(metadata_);
  64   DCHECK_EQ(metadata_->fingerprint, metadata.fingerprint);
  65
  66   UpdateMetadata(make_scoped_ptr(new LogoMetadata(metadata)));
  67   WriteMetadata();
  68 }
  69
  70 const LogoMetadata* LogoCache::GetCachedLogoMetadata() {
  71   DCHECK(thread_checker_.CalledOnValidThread());
  72   ReadMetadataIfNeeded();
  73   return metadata_.get();
  74 }
  75
  76 void LogoCache::SetCachedLogo(const EncodedLogo* logo) {
  77   DCHECK(thread_checker_.CalledOnValidThread());
  78   scoped_ptr<LogoMetadata> metadata;
  79   if (logo) {
  80     metadata.reset(new LogoMetadata(logo->metadata));
  81     logo_num_bytes_ = static_cast<int>(logo->encoded_image->size());
  82   }
  83   UpdateMetadata(metadata.Pass());
  84   WriteLogo(logo ? logo->encoded_image : NULL);
  85 }
  86
  87 scoped_ptr<EncodedLogo> LogoCache::GetCachedLogo() {
  88   DCHECK(thread_checker_.CalledOnValidThread());
  89
  90   ReadMetadataIfNeeded();
  91   if (!metadata_)
  92     return scoped_ptr<EncodedLogo>();
  93
  94   scoped_refptr<base::RefCountedString> encoded_image =
  95       new base::RefCountedString();
  96   if (!base::ReadFileToString(GetLogoPath(), &encoded_image->data())) {
  97     UpdateMetadata(scoped_ptr<LogoMetadata>());
  98     return scoped_ptr<EncodedLogo>();
  99   }
 100
 101   if (encoded_image->size() != static_cast<size_t>(logo_num_bytes_)) {
 102     // Delete corrupt metadata and logo.
 103     DeleteLogoAndMetadata();
 104     UpdateMetadata(scoped_ptr<LogoMetadata>());
 105     return scoped_ptr<EncodedLogo>();
 106   }
 107
 108   scoped_ptr<EncodedLogo> logo(new EncodedLogo());
 109   logo->encoded_image = encoded_image;
 110   logo->metadata = *metadata_;
 111   return logo.Pass();
 112 }
 113
 114 // static
 115 scoped_ptr<LogoMetadata> LogoCache::LogoMetadataFromString(
 116     const std::string& str, int* logo_num_bytes) {
 117   scoped_ptr<base::Value> value(base::JSONReader::Read(str));
 118   base::DictionaryValue* dict;
 119   if (!value || !value->GetAsDictionary(&dict))
 120     return scoped_ptr<LogoMetadata>();
 121
 122   scoped_ptr<LogoMetadata> metadata(new LogoMetadata());
 123   if (!dict->GetString(kSourceUrlKey, &metadata->source_url) ||
 124       !dict->GetString(kFingerprintKey, &metadata->fingerprint) ||
 125       !dict->GetString(kOnClickURLKey, &metadata->on_click_url) ||
 126       !dict->GetString(kAltTextKey, &metadata->alt_text) ||
 127       !dict->GetString(kMimeTypeKey, &metadata->mime_type) ||
 128       !dict->GetBoolean(kCanShowAfterExpirationKey,
 129                         &metadata->can_show_after_expiration) ||
 130       !dict->GetInteger(kNumBytesKey, logo_num_bytes) ||
 131       !GetTimeValue(*dict, kExpirationTimeKey, &metadata->expiration_time)) {
 132     return scoped_ptr<LogoMetadata>();
 133   }
 134
 135   return metadata.Pass();
 136 }
 137
 138 // static
 139 void LogoCache::LogoMetadataToString(const LogoMetadata& metadata,
 140                                      int num_bytes,
 141                                      std::string* str) {
 142   base::DictionaryValue dict;
 143   dict.SetString(kSourceUrlKey, metadata.source_url);
 144   dict.SetString(kFingerprintKey, metadata.fingerprint);
 145   dict.SetString(kOnClickURLKey, metadata.on_click_url);
 146   dict.SetString(kAltTextKey, metadata.alt_text);
 147   dict.SetString(kMimeTypeKey, metadata.mime_type);
 148   dict.SetBoolean(kCanShowAfterExpirationKey,
 149                   metadata.can_show_after_expiration);
 150   dict.SetInteger(kNumBytesKey, num_bytes);
 151   SetTimeValue(dict, kExpirationTimeKey, metadata.expiration_time);
 152   base::JSONWriter::Write(&dict, str);
 153 }
 154
 155 base::FilePath LogoCache::GetLogoPath() {
 156   return cache_directory_.Append(FILE_PATH_LITERAL("logo"));
 157 }
 158
 159 base::FilePath LogoCache::GetMetadataPath() {
 160   return cache_directory_.Append(FILE_PATH_LITERAL("metadata"));
 161 }
 162
 163 void LogoCache::UpdateMetadata(scoped_ptr<LogoMetadata> metadata) {
 164   metadata_ = metadata.Pass();
 165   metadata_is_valid_ = true;
 166 }
 167
 168 void LogoCache::ReadMetadataIfNeeded() {
 169   if (metadata_is_valid_)
 170     return;
 171
 172   scoped_ptr<LogoMetadata> metadata;
 173   base::FilePath metadata_path = GetMetadataPath();
 174   std::string str;
 175   if (base::ReadFileToString(metadata_path, &str)) {
 176     metadata = LogoMetadataFromString(str, &logo_num_bytes_);
 177     if (!metadata) {
 178       // Delete corrupt metadata and logo.
 179       DeleteLogoAndMetadata();
 180     }
 181   }
 182
 183   UpdateMetadata(metadata.Pass());
 184 }
 185
 186 void LogoCache::WriteMetadata() {
 187   if (!EnsureCacheDirectoryExists())
 188     return;
 189
 190   std::string str;
 191   LogoMetadataToString(*metadata_, logo_num_bytes_, &str);
 192   base::WriteFile(GetMetadataPath(), str.data(), static_cast<int>(str.size()));
 193 }
 194
 195 void LogoCache::WriteLogo(scoped_refptr<base::RefCountedMemory> encoded_image) {
 196   if (!EnsureCacheDirectoryExists())
 197     return;
 198
 199   if (!metadata_ || !encoded_image) {
 200     DeleteLogoAndMetadata();
 201     return;
 202   }
 203
 204   // To minimize the chances of ending up in an undetectably broken state:
 205   // First, delete the metadata file, then update the logo file, then update the
 206   // metadata file.
 207   base::FilePath logo_path = GetLogoPath();
 208   base::FilePath metadata_path = GetMetadataPath();
 209
 210   if (!base::DeleteFile(metadata_path, false))
 211     return;
 212
 213   if (base::WriteFile(
 214           logo_path,
 215           encoded_image->front_as<char>(),
 216           static_cast<int>(encoded_image->size())) == -1) {
 217     base::DeleteFile(logo_path, false);
 218     return;
 219   }
 220
 221   WriteMetadata();
 222 }
 223
 224 void LogoCache::DeleteLogoAndMetadata() {
 225   base::DeleteFile(GetLogoPath(), false);
 226   base::DeleteFile(GetMetadataPath(), false);
 227 }
 228
 229 bool LogoCache::EnsureCacheDirectoryExists() {
 230   if (base::DirectoryExists(cache_directory_))
 231     return true;
 232   return base::CreateDirectory(cache_directory_);
 233 }
 234
 235 }  // namespace search_provider_logos